Conventional pendulum devices (e.g., tilt sensors and inclinometers) can be used to measure the pitch angle (incline, inclination) of a vehicle at rest or at constant speed. However, conventional pendulum devices do not provide a reliable measurement of a vehicle's pitch angle under conditions of hard forward acceleration or hard braking. Under such conditions, the pendulum arm will swing or deflect in response to acceleration, no longer providing a reliable measurement of the vehicle's pitch angle. For at least these reasons, a conventional pendulum device cannot be used to monitor the pitch angle of an accelerating vehicle.
One solution to this problem is to use a gyroscope to measure pitch angle changes, optionally in combination with a pendulum device or an accelerometer. The output signal from the gyroscope device is then mathematically integrated to determine the pitch angle of the vehicle, even under acceleration. These gyroscope devices are subject to drift, must often be calibrated or zeroed, are expensive to manufacture and purchase.
The present invention provides a pendulum device that monitors a vehicle's pitch angle, correcting for the inherent error of the pendulum device due to the vehicle's acceleration. This pitch data is then used to affect engine or braking adjustments to avoid catastrophic vehicle pitch angle changes.